Use internally more precise types for typeParameters, remove many casts.

Change-Id: I9d8326c00a2b50aadd4310979e0ec936bfe5e66e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/440780
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Commit-Queue: Paul Berry <paulberry@google.com>
Reviewed-by: Paul Berry <paulberry@google.com>

pkg/analyzer/lib/src/dart/constant/utilities.dart

@@ -157,8 +157,7 @@ class ConstantFinder extends RecursiveAstVisitor<void> {
       if (fragment != null) {
         var element = fragment.element;
         constantsToCompute.add(element);
-        // TODO(scheglov): remove cast
-        constantsToCompute.addAll(element.baseElement.formalParameters.cast());
+        constantsToCompute.addAll(element.baseElement.formalParameters);
       }
     }
   }

pkg/analyzer/lib/src/dart/element/display_string_builder.dart

@@ -171,7 +171,7 @@ class ElementDisplayStringBuilder {
     _writeType(element.returnType);
     _write(' Function');
     _writeTypeParameters(element.typeParameters);
-    _writeFormalParameters(element.formalParameters.cast(), forElement: true);
+    _writeFormalParameters(element.formalParameters, forElement: true);
   }
 
   void writeGetterElement(GetterElementImpl element) {

pkg/analyzer/lib/src/dart/element/element.dart

@@ -2204,7 +2204,7 @@ abstract class ExecutableElementImpl extends FunctionTypedElementImpl
   ExecutableFragmentImpl get firstFragment;
 
   @override
-  List<FormalParameterElementMixin> get formalParameters {
+  List<FormalParameterElementImpl> get formalParameters {
     _ensureReadResolution();
     return firstFragment.formalParameters
         .map((fragment) => fragment.asElement2)
@@ -3830,7 +3830,7 @@ class GenericFunctionTypeElementImpl extends FunctionTypedElementImpl
   GenericFunctionTypeFragmentImpl get firstFragment => _wrappedElement;
 
   @override
-  List<FormalParameterElement> get formalParameters =>
+  List<FormalParameterElementImpl> get formalParameters =>
       _wrappedElement.formalParameters
           .map((fragment) => fragment.element)
           .toList();
@@ -5132,7 +5132,7 @@ abstract class InterfaceFragmentImpl extends InstanceFragmentImpl
   List<InterfaceTypeImpl> _interfaces = const [];
 
   /// This callback is set during mixins inference to handle reentrant calls.
-  List<InterfaceType>? Function(InterfaceFragmentImpl)? mixinInferenceCallback;
+  List<InterfaceTypeImpl>? Function(InterfaceFragmentImpl)? mixinInferenceCallback;
 
   InterfaceTypeImpl? _supertype;
 
@@ -5213,9 +5213,7 @@ abstract class InterfaceFragmentImpl extends InstanceFragmentImpl
     if (mixinInferenceCallback != null) {
       var mixins = mixinInferenceCallback!(this);
       if (mixins != null) {
-        // TODO(paulberry): eliminate this cast by changing the type of
-        // `InterfaceElementImpl.mixinInferenceCallback`.
-        return _mixins = mixins.cast();
+        return _mixins = mixins;
       }
     }
 
@@ -7682,10 +7680,8 @@ class MixinFragmentImpl extends InterfaceFragmentImpl implements MixinFragment {
     return _superclassConstraints;
   }
 
-  set superclassConstraints(List<InterfaceType> superclassConstraints) {
-    // TODO(paulberry): eliminate this cast by changing the type of the
-    // `superclassConstraints` parameter.
-    _superclassConstraints = superclassConstraints.cast();
+  set superclassConstraints(List<InterfaceTypeImpl> superclassConstraints) {
+    _superclassConstraints = superclassConstraints;
   }
 
   @override
@@ -8739,7 +8735,7 @@ abstract class PropertyInducingElementImpl extends VariableElementImpl
     if (element.setter case var setterElement?) {
       if (setterElement.isSynthetic) {
         setterElement.returnType = VoidTypeImpl.instance;
-        (setterElement.formalParameters.single as FormalParameterElementImpl)
+        setterElement.formalParameters.single
             .type = type;
       }
     }
@@ -8926,7 +8922,7 @@ class SetterElementImpl extends PropertyAccessorElementImpl
   }
 
   FormalParameterElementImpl get valueFormalParameter {
-    return formalParameters.single as FormalParameterElementImpl;
+    return formalParameters.single;
   }
 
   @override

pkg/analyzer/lib/src/dart/element/member.dart

@@ -224,7 +224,7 @@ abstract class ExecutableMember extends Member
           );
         default:
           return ParameterMember(
-            baseElement: element as FormalParameterElementImpl,
+            baseElement: element,
             substitution: substitution,
           );
       }

pkg/analyzer/lib/src/dart/resolver/resolution_visitor.dart

@@ -1656,7 +1656,7 @@ class ResolutionVisitor extends RecursiveAstVisitor<void> {
       for (var variable in variables.values) {
         _define(variable);
       }
-      guardedPattern.variables = variables.cast();
+      guardedPattern.variables = variables;
       guardedPattern.whenClause?.accept(this);
       if (then != null) {
         then();

pkg/analyzer/lib/src/summary2/default_value_resolver.dart

@@ -70,7 +70,7 @@ class DefaultValueResolver {
   }) {
     for (var formalParameter in element.formalParameters) {
       _formalParameterElement(
-        formalParameter as FormalParameterElementImpl,
+        formalParameter,
         enclosingInterfaceElement: enclosingInterfaceElement,
         enclosingExecutableElement: element,
       );

pkg/analyzer/lib/src/summary2/instance_member_inferrer.dart

@@ -259,7 +259,7 @@ class InstanceMemberInferrer {
       if (setter != null) {
         if (overriddenSetters.any((s) => _isCovariantSetter(s.baseElement))) {
           var formalParameter = setter.formalParameters[0];
-          (formalParameter as FormalParameterElementImpl).inheritsCovariant =
+          formalParameter.inheritsCovariant =
               true;
         }
       }
@@ -492,7 +492,7 @@ class InstanceMemberInferrer {
     for (var index = 0; index < formalParameters.length; index++) {
       var formalParameter = formalParameters[index];
       _inferParameterCovariance(
-        formalParameter as FormalParameterElementImpl,
+        formalParameter,
         index,
         overriddenElements,
       );

pkg/analyzer/lib/src/summary2/types_builder.dart

@@ -45,11 +45,11 @@ bool _isInterfaceTypeInterface(InterfaceType type) {
   return true;
 }
 
-List<InterfaceType> _toInterfaceTypeList(List<NamedType>? nodeList) {
+List<InterfaceTypeImpl> _toInterfaceTypeList(List<NamedType>? nodeList) {
   if (nodeList != null) {
     return nodeList
         .map((e) => e.type)
-        .whereType<InterfaceType>()
+        .whereType<InterfaceTypeImpl>()
         .where(_isInterfaceTypeInterface)
         .toList();
   }
@@ -187,8 +187,7 @@ class TypesBuilder {
         case SetterElementImpl():
           element.returnType = returnType;
           var valueElement =
-              element.formalParameters.singleOrNull
-                  as FormalParameterElementImpl?;
+              element.formalParameters.singleOrNull;
           var valueNode =
               node.functionExpression.parameters?.parameters.firstOrNull;
           var valueNodeElement = valueNode?.declaredFragment!.element;
@@ -231,8 +230,7 @@ class TypesBuilder {
         case SetterElementImpl():
           element.returnType = returnType;
           var valueElement =
-              element.formalParameters.singleOrNull
-                  as FormalParameterElementImpl?;
+              element.formalParameters.singleOrNull;
           var valueNode = node.parameters?.parameters.firstOrNull;
           var valueNodeElement = valueNode?.declaredFragment!.element;
           var valueNodeType = valueNodeElement?.type;
@@ -268,8 +266,7 @@ class TypesBuilder {
             }
             if (variableElement.setter case var setterElement?) {
               setterElement.returnType = VoidTypeImpl.instance;
-              (setterElement.formalParameters.single
-                      as FormalParameterElementImpl)
+              setterElement.formalParameters.single
                   .type = type;
             }
           }
@@ -644,14 +641,14 @@ class _MixinsInference {
   /// we are inferring the [element] now, i.e. there is a loop.
   ///
   /// This is an error. So, we return the empty list, and break the loop.
-  List<InterfaceType> _callbackWhenLoop(InterfaceFragmentImpl element) {
+  List<InterfaceTypeImpl> _callbackWhenLoop(InterfaceFragmentImpl element) {
     element.mixinInferenceCallback = null;
-    return <InterfaceType>[];
+    return <InterfaceTypeImpl>[];
   }
 
   /// This method is invoked when mixins are asked from the [element], and
   /// we are not inferring the [element] now, i.e. there is no loop.
-  List<InterfaceType>? _callbackWhenRecursion(InterfaceFragmentImpl element) {
+  List<InterfaceTypeImpl>? _callbackWhenRecursion(InterfaceFragmentImpl element) {
     var declaration = _declarations[element];
     if (declaration != null) {
       _inferDeclaration(declaration);

pkg/analyzer/test/src/dart/resolution/constant_test.dart

@@ -40,7 +40,7 @@ const a = const A();
 
     var aLib = findElement2.import('package:test/a.dart').importedLibrary!;
     var aConstructor = aLib.getClass('A')!.constructors.single;
-    var p = aConstructor.formalParameters.single as FormalParameterElementImpl;
+    var p = aConstructor.formalParameters.single;
 
     // To evaluate `const A()` we have to evaluate `{int p}`.
     // Even if its value is `null`.